| Cu2O powders obtained via liquid phase method have properties of small particle size,high purity and preferable dispersion. However, the use of toxic substances as reductants such as N2H4 and Na2SO3 or additives may cause a high environmental treatment costs in many processes. The purpose of this study is to develop a green, method for preparation of monodisperse Cu2O powder using glucose as a reductant without any additives.Using glucose as a reductant in the alkaline system, the effects of mixing mode of reagents, precursor properties,reaction temperature,pH values and reaction reagents concentration on the morohology and particle size of Cu2O powder were investigated,and the mechanism effecting the morohology and particle size of Cu2O powder were simply discussed.The detail conclusions are as follows:Spherical Cu2O crystal could be obtained via different mixing modes of reagents. Among all modes, Cu2O crystal with properties of narrow particle size distribution,preferable dispersibility and good experimental repeatability were obtained via mixing mode of reagents which it putted NaOH into CuSO4 solution lowly,then added C6H12O6 solution.Cubic Cu2O crystal was obtained when CuO acted as a precursor; Spherical Cu2O crystal which had preferable dispersibility and narrow particle size distribution were obtained when the mixture of Cu2O and Cu(OH)2 acted as precursors. However, under this condition, the experiment had poor repeatability and the particle size varied widely.The change in reaction temperature did not remarkably influence morphology of Cu2O crystal but influenced its particle size. The particle size gradually decreased with rising reaction temperature. At 40℃, the average particle size reached 3.11um and the particle size distribution was very wide.The average particle size was 2.08um at 50℃and 1.80um at 60℃respectively. Further more, the particle size distribution was the narrowest at 50C. At higher reaction temperature than 60℃, Cu2O powders obtained was quasi-spherical, while reaction temperature kept up rising, the average particle size changed lightly from 1.80um decreasing to 1.63um.With rising NaOH concentration, the morphology of Cu2O powder transited from spheric to Quasi-spherical,finally transited to octahedral. When the NaOH concentration was from 2.50mol/L increasing to 3.125 mol/L, the average particle size of spherical Cu2O powders gradually changed from 1.61um increasing to 3.27um,but its size distribution became wide and particle size became not uniform.Cubic Cu2O powders were obtained when glucose concentration was 0.40mol/L (insufficient amount of glucose); Octahedral Cu2O powers were obtained when glucose concentration was 0.50mol/L (equivalent amount of glucose); Quasi-spherical Cu2O powders were obtained when glucose concentration were 0.625mol/L and 0.75mol/L. However. when glucose concentration was greater than or equal to 1.00mol/L, the average particle size of spherical Cu2O powders gradually decreased from 2.08 um to 0.67um with rising glucose concentration. At the same time, the standard deviation of particle size gradually decreased.With low CuSO4 concentration (less than or equal to 0.25mol/L), the morphology of Cu2O powders were mainly cubic. When CuSO4 concentration was equal to 0.125mol/L, cubic powders with uniform shape,well-dispersibility and narrow particle size distribution were obtained. But, when CuSO4 concentration was equal to 0.50mol/L, the average particle size of spherical Cu2O powders gradually increased from 1.81um to 2.08um with rising CuSO4 concentration.Based on the experimental results mentioned above, it has been achieved to control the shape and particle size of Cu2O crystal and this method has advantages that the devices is simple,the cost is low,so it can provide some basis for industrial production. |
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